Packaging bags formed by forming, into a bag shape, a multifold film formed by stacking multiple films have been proposed as bags for packaging fluid, semifluid, powder, or the like. In such a packaging bag, the films forming the multifold film are unbonded over a wide range and can sideslip with respect to each other in the unbonded range. Thus, even if a pinhole occurs in one film, the other films can remain intact. Even if one film receives a bending stress, the other film can slide and escape. Therefore, such a packaging bag has advantageous effects, including improvements in mechanical properties such as pinhole resistance and impact resistance.
For example, Patent Literature 1 discloses a packaging bag and a manufacturing method thereof. This packaging bag is formed by bending a multifold film into a tubular shape and then sealing the edges and has containing space for containing an object to be packaged.